1. Field of the Invention
This invention relates generally to a transmission and more particularly to a transmission utilizing a unique shift collar, shift fork and/or shift drum and/or a trap door.
2. Description of the Prior Art
Examples of other transmissions for motorcycles are found in U.S. Pat. Nos. 4,455,884, assigned to Honda and 6,308,797 assigned to Harley-Davidson Motor Company Group. The industry is constantly trying to address issues with existing designs and provide better solutions for areas that can be improved. For instance, for shifting mechanisms, better lubrication will assist in providing a better shifting mechanism. Reducing the weight of the shifting mechanism also leads to easier shifting. The present invention addresses these issues and provides for an improved shifting mechanism.
The engagement of the individual gears, as the transmission is shifted through the various gears is also an area that is of concern. The typical transmission will use a plurality of dogs and pockets to engage the gear. Mechanisms and methods for a smoother engagement are viewed as areas that can be improved upon to provide for a better motorcycle transmission.
Axial play of the shafts of a transmission need to be controlled. In the manufacturing of motorcycle transmissions, there is a tolerance stack up between bearing width, retaining ring width, and the depth of the bearing pocket to the location of the retaining ring groove. Excessive axial play on the main shaft can cause a motorcycle clutch to partially disengage during acceleration, causing the clutch to slip and possibly fail prematurely. Motorcycle transmissions that utilize spur gear designs do not generate an axial force like helical gears generate. Accordingly, for helical gears it is preferred to reduce axial shaft movement so as to achieve consistent clutch lever end play, which is a rider perception.
The present invention addresses these issues of prior art motorcycle transmissions.